People need to wear a face mask or other personal protective equipment when they work in dangerous areas for the sake of safety. For example, a firefighter must wear a face mask or a self contained breathing apparatus when battling a fire. Firefighters and other first responders often rely on wireless communications, for example, radio communications to successfully and safely perform their tasks. When a face mask or the personal protective equipment is worn, it becomes difficult to conduct face-to-face communication or wireless communication, for example, person-to-radio communication because speech is heavily attenuated by the face mask or the personal protective equipment. Moreover, any communication can be severely degraded by background noise. In an extremely noisy environment, a communication device, for example, a radio can hardly pick up any clean speech at all. The firefighter has to hold the communication device close to the mouth and shout loudly in order to be heard accurately. Often, in order to communicate effectively through the communication device, the firefighter has to remove the protective face mask, which compromises health and safety of the firefighter. There is a need for users wearing the face mask or the personal protective equipment to have very clear and effective communications in such a high noise environment. Poor communication not only decreases the working efficiency but can also be fatal. Hence, there is a need for a wearable communication system that allows the user wearing the face mask, the personal protective equipment, or any other wearable unit to maintain clear and effective communications in high noise environments.
A few solutions to improve the efficiency of communications have been developed and utilized. Operational procedures, for example, hand and arm signals, provide a primitive solution and are not effective for scenarios requiring hands free communications. Commercial noise cancellation devices that can cancel ambient noise have been developed, although these noise cancellation devices can only work well when communicating without radios or when communicating through radios in a push to talk communication mode.
As a component of the noise cancellation devices, different kinds of microphones have been employed to improve the efficiencies of communications in the market, namely, an in-the-mask microphone, a bone conduction microphone, and an adhesive microphone. The first option, namely, the in-the-mask microphone integrated with the face mask, is an expensive solution since a user, for example, a first responder needs to replace an entire wearable unit, for example, the self contained breathing apparatus. The self contained breathing apparatus has a potential risk of air leakage because the in-the-mask microphone needs to be wired out for connection to an external radio. Moreover, speech becomes distorted as speech passes through the self contained breathing apparatus. The second option is the use of the bone conduction microphone, but the bone conduction microphone needs to have a tight contact with a human body. This contact needs to be either directly on the skull or the throat of the user, which makes the user uncomfortable. The installation of the bone conduction microphone is not stable since the microphone cannot be rigidly fixed to the human body. The adhesive microphone attached to the outside of the self contained breathing apparatus is the third option. However, the adhesive microphone is not considered a complete solution due to the following reasons: (1) no further active noise reduction technology has been applied. As a result, the noise level is still not low enough for comfortable listening; (2) the speech picked up by the adhesive microphone sounds different from normal speech because the speech is excited within the self contained breathing apparatus, so the person who listens to the speech has difficulty in identifying who is talking; (3) the adhesive microphone option does not work with those first responders who do not wear a face mask but work in a high noise environment.
Besides the above drawbacks, no existing commercial noise cancellation device has adequately implemented a voice operated switch (VOX) communication mode with radios. In the VOX communication mode, the radio acts as an open microphone and sends signals out only when speech is detected. With these commercial noise cancellation devices, the VOX communication mode with radios is not robust enough against background noise, which may cause the radio to continuously transmit unwanted noise across a network and interfere with others' abilities to use the same frequency. To address the above problems, a solution to improve communications is highly desirable.
Hence, there is a long felt but unresolved need for a method and a wearable communication system that provides a noise cancellation device that supports personal face-to-face communication, person-to-radio communication, and wireless communication in a high noise environment. Moreover, there is a need for a noise cancellation device that works effectively in high noise environments through radios in a push to talk (PTT) communication mode and a voice operated switch (VOX) communication mode, with and without radios.